Construction Techniques,Equipments and Practices

7/24/2019 Construction Techniques,Equipments and Practices

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CE2203CONSTRUCTION TECHNIQUES, EQUIPMENT AND PRACTICES 4 0 0 4

OBJECTIVE

The main objective of this course is to make the student aware of the various construction

techniques, practices and the equipment needed for different types of construction activities. At

the end of this course the student shall have a reasonable knowledge about the various

construction procedures for sub to super structure and also the equipment needed for

construction of various types of structures from foundation to super structure.

UNIT I CONCRETE TECHNOLOGY 12

CementsGrade of cements - manufacture of cementconcrete chemicals and ApplicationsMix design conceptmix design as per BIS & ACI methodsmanufacturing of concrete

Batchingmixingtransportingplacingcompaction of concretecuring and finishing.

Testing of fresh and hardened concretequality of concrete - Nondestructive testing.

UNIT II CONSTRUCTION PRACTICES 13

Specifications, details and sequence of activities and construction co-ordinationSite Clearance

MarkingEarthwork - masonrystone masonryBond in masonry - concrete hollow block

masonryflooringdamp proof coursesconstruction jointsmovement and expansion joints

pre cast pavementsBuilding foundationsbasementstemporary shedcentering and

shutteringslip formsscaffoldingsde-shuttering formsFabrication and erection of steel

trussesframesbraced domeslaying brickweather and water proofroof finishes

acoustic and fire protection.

UNIT III SUB STRUCTURE CONSTRUCTION 13

Techniques of Box jackingPipe Jacking -under water construction of diaphragm walls and

basement-Tunneling techniquesPiling techniques - well and caisson - sinking cofferdam -

cable

anchoring and grouting-driving diaphragm walls, sheet piles - shoring for deep cutting - well

points -Dewatering and stand by Plant equipment for underground open excavation.

UNIT IV SUPER STRUCTURE CONSTRUCTION 12

Launching girders, bridge decks, off shore platformsspecial forms for shells - techniques for


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heavy decksin-situ pre-stressing in high rise structures, Material handling - erecting light

weight

components on tall structures - Support structure for heavy Equipment and conveyors -Erection

of articulated structures, braced domes and space decks.

UNIT V CONSTRUCTION EQUIPMENT 10

Selection of equipment for earth work - earth moving operations - types of earthwork equipment

-

tractors, motor graders, scrapers, front end waders, earth moversEquipment for foundation and

pile driving. Equipment for compaction, batching and mixing and concreting - Equipment for

material handling and erection of structures - Equipment for dredging, trenching, tunneling,

TOTAL: 60 PERIODS


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UNIT I CONCRETE TECHNOLOGY

TYPES OF CEMENT

OPC33,OPC43 and OPC53 grade


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cemnt

CHEMICAL ADMIXTURES OF CONCRETE

Water-reducing admixture / Plasticizers:

These admixtures are used for following purposes:

1. To achieve a higher strength by decreasing the water cement ratio at the same workability as

an admixture free mix.

2. To achieve the same workability by decreasing the cement content so as to reduce the heat of

hydration in mass concrete.

3. To increase the workability so as to ease placing in accessible locations

4. Water reduction more than 5% but less than 12%

Actions involved:

1. Dispersion:

Surface active agents alter the physic chemical forces at the interface. They are adsorbed on the

cement particles, giving them a negative charge which leads to repulsion between the particles.

Electrostatic forces are developed causing disintegration and the free water become available for

workability.

2. Lubrication:

As these agents are organic by nature, thus they lubricate the mix reducing the friction and

increasing the workability.

3. Retardation:


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A thin layer is formed over the cement particles protecting them from hydration and increasing

the setting time. Most normal plasticizers give some retardation, 3090 minutes

Super Plasticizers:

high range water reducer

The commonly used Super Plasticizers are as follows:

Sulphonated melamine formaldehyde condensates (SMF)

Give 1625%+ water reduction. SMF gives little or no retardation, which makes them

very effective at low temperatures or where early strength is most critical.

However, at higher temperatures, they lose workability relatively quickly. SMF generally

give a good finish and are colorless, giving no staining in white concrete.

They are therefore often used where appearance is important.

Sulphonated naphthalene formaldehyde condensates (SNF)

Typically give 1625%+ water reduction. They tend to increase the entrapment of larger,

unstable air bubbles. This can improve cohesion but may lead to more surface defects.

Retardation is more than with SMF but will still not normally exceed 90 minutes. SNF is

a very cost-effective.

Polycarboxylate ether super plasticizers (PCE)

Typically give 2035%+ water reduction. They are relatively expensive per liter but are

very powerful so a lower dose (or more dilute solution) is normally used.

In general the dosage levels are usually higher than with conventional water reducers, and

the possible undesirable side effects are reduced because they do not markedly lower the

surface tension of the water.

Accelerators:

An admixture which, when added to concrete, mortar, or grout, increases the rate of hydration of

hydraulic cement, shortens the time of set in concrete, or increases the rate of hardening or

strength development.

Accelerating admixtures can be divided into groups based on their performance and application:

1. Set Accelerating Admixtures,


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Reduce the time for the mix to change from the plastic to the hardened state.

Set accelerators have relatively limited use, mainly to produce an early set.

2. Hardening Accelerators,

Which increase the strength at 24 hours by at least 120% at 20C and at 5C by at least 130% at

48 hours. Hardening accelerators find use where early stripping of shuttering or very early access

to pavements is required. They are often used in combination with a high range water reducer,

especially in cold conditions.

.

Set Retarders:

The function of retarder is to delay or extend the setting time of cement paste in concrete.

These are helpful for concrete that has to be transported to long distance, and helpful in

placing the concrete at high temperatures.

When water is first added to cement there is a rapid initial hydration reaction, after which

there is little formation of further hydrates for typically 23 hours.

The exact time depends mainly on the cement type and the temperature. This is called the

dormant period when the concrete is plastic and can be placed.

At the end of the dormant period, the hydration rate increases and a lot of calcium silicatehydrate and calcium hydroxide is formed relatively quickly. This corresponds to the

setting time of the concrete.

Retarding admixtures delay the end of the dormant period and the start of setting and

hardening. This is useful when used with plasticizers to give workability retention. Used

on their own, retarders allow later vibration of the concrete to prevent the formation of

cold joints between layers of concrete placed with a significant delay between them.

The mechanism of set retards is based on absorption. The large admixture anions and

molecules are absorbed on the surface of cement particles, which hinders further

reactions between cement and water i.e. retards setting.


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Air Entrained Admixtures:

An addition for hydraulic cement or an admixture for concrete or mortar which causes

air, usually in small quantity, to be incorporated in the form of minute bubbles in the

concrete or mortar during mixing, usually to increase its workability and frost

resistance.

Air-entraining admixtures are surfactants that change the surface tension of the water.

Traditionally, they were based on fatty acid salts or vinsol resin but these have largely

been replaced by synthetic surfactants or blends of surfactants to give improved stability

and void characteristics to the entrained air.

Air entrainment is used to produce a number of effects in both the plastic and the hardened

concrete. These include:

Resistance to freezethaw action in the hardened concrete.

Increased cohesion, reducing the tendency to bleed and segregation in the plastic concrete.

Compaction of low workability mixes including semi-dry concrete.

Stability of extruded concrete.

MANUFACTURING OF CEMENT

Raw materials used

Calcareous materials used are

o Cement rock

o Lime stone

o Marl

o Chalk

o Marine shell

Argillaceous materials used are

o Clay

o shale

o slate


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o blast furnace slag

Process manufacturing cement

Dry process

General

Adopted when the raw materials are quite hard

The process is slow an the product is costly

Process

Lime stone and clay are ground to fine powder separately and are mixed together

Water is added to make a thick paste which contains 14% of moisture

The paste format are dried and off charged into a rotary kiln

The product obtained often calcinations in rotary kiln

The clinker I obtained as a result of incipient fusion and sintering at a temp about 1400c

to 1500 c

The clinker is cooled to preserve the meta stable compounds and there solid solutions

Dispersion of one solid with another solid which made the clinker again heated

Clinker is again cooled and grounded in tube mills where 2-3% gypsum is added

The purpose of adding gypsum is to coat the cement particle by interfering the process of

hydration of cement particles

The flow diagram of dry process

Wet process

The operations are


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Process

The crushed raw materials are fed in to a ball mill and a little water is added

The steel balls in the ball mill pulverized the raw material which form a slurry with water

The slurry is passed through storage tanks where the proportioning of compound is

adjusted to ensure desired chemical composition

The corrected slurry having moisture about 40%,is then fed into rotary kiln

Where it loses moisture and form on to lumps

These are finally burned at 1500 to 1600 c

It becomes clinker at this stage, the clinker is cooled and then grounded in tube mills

While grinding the clinker 3% gypsum I added this is stored in silos and packed

Concrete Mix Design concept

Definition:

Mix design can be defined as the process of selecting suitable ingredients of concrete and

determining their relative proportions with the object of producing concrete of certain

minimum strength and durability as economically as possible.

One of the ultimate aims of studying the various properties of the materials of concrete,

plastic concrete and hardened concrete is to enable a concrete technologist to design a

concrete mix for a particular strength and durability.

The design of concrete mix is not a simple task on account of the widely varying

properties of the constituent materials, the conditions that prevail at the site of work, in

particular the exposure condition, and the conditions that are demanded for a particular

work for which the mix is designed.

Design of concrete mix requires complete knowledge of the various properties of these

constituent materials, these make the task of mix design more complex and difficult.

Design of concrete mix needs not only the knowledge of material properties and

properties of concrete in plastic condition; it also needs wider knowledge and experienceof concreting.

Even then the proportion of the materials of concrete found out at the laboratory requires

modification and re adjustments to suit the field conditions.

With better understanding of the properties, the concrete is becoming more and more an

exact material than in the past.


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The structural designer specifies certain minimum strength; and the concrete technologist

designs the concrete mix with the knowledge of the materials, site exposure conditions

and standard of supervision available at the site of work to achieve this minimum strength

and durability.

Further, the site engineer is required to make the concrete at site, closely following the

parameters suggested by the mix designer to achieve the minimum strength specified by

the structural engineer.

In some cases the site engineer may be required to slightly modify the mix proportions

given by the mix designer.

He also makes cubes or cylinders sufficient in numbers and tests them to confirm the

achievements with respect to the minimum specified strength. Mix designer, earlier, may

have made trial cubes with representative materials to arrive at the value of standard

deviation or coefficient of variation to be used in the mix design.

American Concrete Institute Method of Mix Design 11.3 (ACI Concrete Mix Design)

This method of proportioning was first published in 1944 by ACI committee 613. In 1954 the

method was revised to include, among other modifications, the use of entrained air. In 1970, the

method of ACI mix design became the responsibility of ACI committee 211. We shall now deal

with the latest ACI Committee 211.1 method.

It has the advantages of simplicity in that it:1. Applies equally well

2. With more or less identical procedure to rounded or angular aggregate

3. To regular or light weight aggregates

4. To air entrained or non-air-entrained concretes.

Manufacturing of concrete

Introduction

Production of concrete requires meticulous care at every stage

The ingredients of good and bad concrete are same but good rules are not

Observed it may become bad

Manufacturing of concrete includes the following stages

1. Batching


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2. Mixing

3. Transporting

4. Placing

5. Compacting

6. Curing

7. Finishing

Batching

The measurement of materials for making concrete is known as batching.

Methods of batching

Volume batching

The required ingredients of conc. Are measured by volume basis

o Volume batching is done by various types of gauge boxes

o The gauge boxes are made with comparatively deeper with narrow surface

o Some times bottomless gauge boxes are used but it should be avoided

Volume batching is not a good practice because of the difficulties it offers to granular material.

Some of the sand in loose condition weighs much less than the same volume of dry compacted

soil.

For un important concrete or any small job concrete may be batched by volume.

Weigh batching

It is the correct method of measuring materials for concrete.

Use of weight system in batching ,facilitates accuracy flexibility and simplicity

The different types of weigh batching are there, they are used based on the different

situation.

In small works the weighing arrangement consist of two weighing buckets connected to

the levers of spring loaded dials which indicates the load,


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Mixing

Thorough mixing of materials is essential for the production of uniform concrete

The mixing should ensure that the mass becomes homogeneous uniform in color and

consistency.

Types of mixing

Hand mixing

Machine mixing

Hand mixing

It is practiced for small scale un important concrete works

Hand mixing should be done over a impervious concrete or brick floor sufficiently large

size take one bag of cement .

Spread out and measure d out fine aggregates and course aggregate in alternative layers.

Pour he cement on the top of it and mix them dry by showel, turning the mixture over and

over again until the uniformity of color is achieved.

The uniform mixture is spread out in the thickness of about 20 cm

The water is taken and sprinkled over the mixture and simultaneously turned over

The operation is continued till such time a good uniform homogeneous concrete is

obtained

Machine mixing

Mixing of concrete almost invariably carried ot by machine ,for reinforced concrete work

medium or large scale concrete works .

Machine mixing is not only efficient it is also economical when quantity of concrete to be

produced is large

Type of mixer for mixing concrete

Batch mixer

Batch mixer produce concrete batch by batch with time interval

This is used in normal concrete work


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Batch mixers are two types

Drum types are further classified into tilting ,non tilting and forced action type

The capacity of batch mixer depends on the proportion of the mix

For 1:2:4 ideal mixer 200 liters

For 1:3:6 ideal mixer 280 liters

Mixing time

Concrete mixers are generally designed to run at a speed of 15 to 20 revolutions per minute

For proper mixing it is seen that about 25to 30 revolutions are required in a well designed mixer

It is important that a mixer should not stop in between concreting operations for this requirement

concrete mixer must be kept maintained

Transporting of concrete

Concrete can be imported by variety of methods and equipments

Methods adopted for transportation of concrete

e way


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Mortar pan

This case concrete is carried out in small quantities

This method exposes greater surface area of concrete for drying conditions

This results a geat loss of water particularly in hot weather

Mortar pan must be wetted to start with and must be kept clean

Wheel barrow

Used for transporting concrete in ground level.

This method is employed for hauling concrete in longer distance in case of concrete road

construction.

If the distance is long or ground is rough it is likely that the concrete get segregated due

to vibration

To avoid this, wheel barrows are provided with pneumatic wheel.

Crane bucket and rope way

This is one of the right way for transporting concrete above the ground level

Crane can handle concrete in high rise construction project and are becoming familiar

sites in big cities

Rope way buckets of various sizes are used

Rope way method is adopted for

Concrete works in valley

Construction work of the pier in the river

For dam construction

Truck mixer and dumpers

For large concrete works particularly for concrete to be placed at ground level

These are ordinary open steel tipping lorries

Dumpers having 2-3 cubic meter capacity

Belt conveyors also can be used for


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Chutes

Provided for transporting concrete from ground to lower levelThe surface should have same

slope not flatter than 1 vertical to 2 and a1/2 horizontal

Skip and hoist

Adopted method for transporting concrete vertically for 3 to 4 floors

Mortar pan with staging and human ladder is used for transporting concrete

Transit mixer

This is the equipment for transporting concrete over a big distance particularky ready mix

concrete


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They are truck mounted having a capacity of 4 to 7 m3

The speed of rotation of truck mixer is 4to16 rev/min

A small concrete pump is also mounted on the truck carrying transit mixer

Pumps and pipe lines

Universally accepted method

Starts with the suction stroke for suck the concrete inside the pipe

It has a piston which moves forward and backward to have suction and delivery of concrete

Placing of concrete

Concrete must be placed in a systematic manner to yield optimum results

Some situation where we used provide concrete

Placing concrete within earth mould

Placing concrete with large earth mould or timber plank form work

Placing concrete in layers with in timber or steel shutter

Placing concrete with in usual form work

Placing concrete under water


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Placing concrete within earth mould

Concrete is invariably as foundation bed below the walls and columns

Before placing concrete

All loose earth must be removed

Roots of trees must be cut

If surface is dry must be made just damp

If it is too wet or rain soaked the water slush must be removed

Placing concrete with large earth mould or timber plank form work

For construction of road slabs,air field slabs and ground floor slabs in building conc os placed in

this method

The ground surface must be free from loose earth pool of water ,grass or roots or leaves

The earth must be compacted well

Poly ethylene film is used in between conc ground to avoid absorption of moisture

Concrete is laid alternative layers to give enough scope for shrinkage

Placing concrete in layers with in timber or steel shutter

This can be used in the following cases

Dam construction

Construction of concrete abutments

Raft for a high rise building

The thickness of layers depend on

Method of compaction

Size of vibrator

Frequency of vibrator used

It is good for laying 15 to 30 cm thick layer of concrete ,for mass concrete it may varie from 35

to 45 cm

Its better to leave the top of the layer rough so that succeeding layer can have the good bond

Placing concrete with in usual form work

This can be adopt for Column ,beam and floors

Rules that should be followed while placing the concrete


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The concrete must be placed very care fully a small quantity at a time so that they will not block

the entry of subsequent concrete

Placing concrete under water

Concrete is often required to be placed under water or I a trench filled with slurry

In such a cases use of bottom slurry buckets or termic pipes are used

In the bottom bucket concrete is taken through water in a water tight box or bucket

reaching final place of deposition

The bottom is made to open by some mechanism and the whole concrete is dumped

slowly.

Compaction of concrete

Compaction of concrete is the process adopted for expelling the entrapped air from the concrete

Method for compacting concrete

Hand compaction

Compaction by vibrator

Compaction by pressure and jolting

Compaction by spinning

Hand compaction

Adopted in case of unimportant concrete

This can be adopted when mechanical mean cannot be used

It consist of

Roding


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Poking the concrete with about 2m long 16 mm dia rod to poke the concrete reinforcement

Ramming

Should be done with care

Permitted in unreinforced foundation concrete in ground floor construction

Tamping

The thickness of conc should be comparatively less

Consist of beating the op surface by wooden cross beam

The section of wooden beam is about 10x10 cm

Compaction by vibrators

We can place the concrete economically when compared to hand compaction

The use of vibrators may be essential for the production of good concrete

Type of vibrators

Internal vibrator

Formwork vibrator

Table vibrator

Platform vibrator

Surface vibrator

Vibratory rollers

Compaction by pressure and jolting

This is one of the effective method of compacting dry concrete

Often used for compacting hollow block ,cavity blocks concrete blocks

The stiff concrete is vibrated pressed and also given jolts

With the combined action of the three the stiff conc gets compacted to an dense form to

give good strength and volume

Compaction by spinning

This is one of the recent method of the compacting concrete This is adopted for fabrication of concrete pipes

The plastic concrete when at every high speed get well compacted by centrifugal force

Potential products such as spun pipes are compacted by spinning process


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Vibratory rollers

One of the recent methods of compacting very lean or dry concrete

The concrete compacted by rollers can be called as roller concrete

Tests on concrete

Concrete Slump Test

This test is performed to check the consistency of freshly made concrete.

The slump test is done to make sure a concrete mix is workable.

The measured slump must be within a set range, or tolerance, from the target slump.

Workability of concrete is mainly affected by consistency i.e. wetter mixes will be more

workable than drier mixes, but concrete of the same consistency may vary in workability.

It can also be defined as the relative plasticity of freshly mixed concrete as indicative of

its workability.

Tools and apparatus used for slump test (equipment):

1. Standard slump cone (100 mm top diameter x 200 mm bottom diameter x 300 mm high)

2. Small scoop

3. Bullet-nosed rod (600 mm long x 16 mm diameter)

4. Rule

5. Slump plate (500 mm x 500 mm)

Procedure of slump test for concrete:

clean, firm, level and non-absorbent. Collect a sample of concrete to perform the slum test

.

e with the sample. Compact

the concrete by 'rodding' 25 times. Rodding means to push a steel rod in and out of the concrete

to compact it into the cylinder, or slump cone. Always rod in a definite pattern, working from

outside into the middle.

to 2/3 and again rod 25 times, just into the top of the first layer.


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cone till it overflows.

ion. Clean any concrete from around

the base and top of the cone, push down on the handles and step off the footpieces.

Turn the cone upside down and place the rod across the up-turned cone.

Take several measurements and report the average distance to the top of the sample.If the sample

fails by being outside the tolerance (ie the slump is too high or too low), another must be taken.

If this also fails the remainder of the batch should be rejected.

Compression Test

The compression test shows the compressive strength of hardened concrete.

The compression test shows the best possible strength concrete can reach in perfect

conditions.

The compression test measures concrete strength in the hardened state. Testing should

always be done carefully. Wrong test results can be costly.

The testing is done in a laboratory off-site. The only work done on-site is to make a

concrete cylinder for the compression test. The strength is measured in Megapascals (MPa) and is commonly specified as a

characteristic strength of concrete measured at 28 days after mixing.

The compressive strength is a measure of the concretes ability to resist loads which tend

to crush it.

Apparatus for compression test

Cylinders (100 mm diameter x 200 mm high or 150 mm diameter x 300 mm high) (The small

cylinders are normally used for most testing due to their lighter weight)

1. Small scoop

2. Bullet-nosed rod (600 mm x 16 mm)

3. Steel float

4. Steel plate


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Procedure for compression test of concrete

and firm surface, ie the steel plate. Collect a sample.

ld with concrete then compact by rodding 25 times. Cylinders

may also be compacted by vibrating using a vibrating table.

mould till overflowing.

f the top with the steel float and clean any concrete from around the mould.

red and crushed

to test compressive strength


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UNIT II CONSTRUCTION PRACTICES

Sequence of activities and construction co-ordination

Planning

Planning is considered as a precondition measures before attending any development program

Particularly planning is more important in the following area

When the fund available are limited

The total requirement is much higher

Sequence of operation

It is always desirable to divide large projects into several construction stages

For prepare progress of construction each stage may be constructed under separate

contraction

It should be carried out in the proper method and arrangement

Before starting to construct the structure we must go for the sequence of operation in the

project it is better way o arrange the labour material and equipment

Following are the sequence of operation in a highway project

Site clearance

Earth work for laying embankment

Construction of drainage works

Construction of pavement structures

Installation of light poles and road signals

MARKING, SETTING OUT OF FOUNDATION

Setting out is the process of laying down the excavation lines and centre lines on the

ground before excavation is started after the foundation design is done

For setting out the foundation of a small building the centre line of the longest outer wall

of the building is first marked on the ground by stretching a string between wooden or

mild steel pegs driven at the ends Two pegs one on either from the central peg are driven at the each end of the line

Each peg is equidistant from the central peg and the distance between the outer pegs

corresponds to the width of foundation trench to be excavated

Each peg may be projected about 25 to 50 mm above ground level may be driven at a

distance of 2m from the edge of excavation


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When the string is stretched joining the corresponding pegs at the two extremities of the

line the boundary of the trench to be excavated can be marked on the ground with dry

lime powders

A right angle can be set out b forming 3, 4 and 5 units long

The centre line of the other wall which is perpendicular to the long wall can be marked

by setting out right angles

All the specifications are made by tape or prismatic compass may be used for setting out

right angles

Similarly outer lines of the foundation trench of each cross wall can be set out

For big project reference pillars of masonry is constructed first, these pillars may be

about 20cm thick and 15cm wider than the width of the foundation

EXCAVATION

Excavation of foundation can be done by manually or with the help of special mechanical

equipments

Manually it can be done by the help of following equipments

o Spade

o Phawrah

o Pick axe

o Crowbar

o Rammer

o Wedge

o Boning rod

o Sledge hammer

o Basket

o Iron pan

o line and pins

Mechanically the excavation can be done by the help of following machineries

o Boom bucket dipper handle

o Trench

o Chain mounted buckets


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o Raking cut

o Vertical cut

FOUNDATION

The foundation is he lower portion of the building, usually located below the ground level, which

transmit the load of super structure to sub soil

Functions of foundation

Types of foundation

Shallow foundation

If the depth of foundation is less than or equal to width of foundation it is called as shallow

foundation

Types of shallow foundation


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Trapezoidal footing

If the independent footings of two columns are connected by a beam it is called as strap footing

A strap footing may be used where the distance between the columns is so great that a combined

trapezoidal footing becomes quite narrow

The strap beam does not remains in contact with soil and thus does not transfer any pressure to

the soil

Mat foundation

A raft or mat is a combined footing that covers the entire beneath a structure

And supports all walls and columns

It is used when the allowable soil pressure is low are the building loads are heavy

It is used to reduce the settlement above highly compressible soil

Rafts may divided into three types

o Solid slab system

o Beam slab system

o Cellular system

Deep foundation

If the depth of foundation is equal to or more than the width of the foundation is called deep

foundation

Types

Deep strip footing

Whenever the depth of strip footing is more than the width it is called as deep strip footing


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Pile foundation

it is a type of deep foundation in which the loads are taken to a low level by means of vertical

members which may be timber or concrete or steel

Types of pile foundation

ng and friction pile

End bearing piles

End bearing piles are used to transfer load through water or soft soil to a suitable bearing stratum

Such piles are used to carry heavy loads to hard strata

Multi storied buildings are invariably founded on end bearing piles, so that the settlements are

minimized

Friction pilesFriction piles are used to transfer loads to a depth of a friction load carrying material by means of

skin friction along the length of the pile

These piles mostly used in granular soil

Combined end bearing and friction pile

These are the piles which transfer the super imposed load both through side friction as well as

end bearing

Such piles are more common, especially the end bearing piles are passed through granular soil

Compaction piles

These piles are used o compact loose soil thus increasing there bearing capacity

The pile tube driven to compact the soil is gradually taken out and sand is filled in its place thus

forming the sand pile


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Pier foundation

A pier foundation consist of a cylindrical column of large diameter to support transfer large

super imposed loads to the firm strata below

Generally pier foundation is shallower in depth than the pile foundation

It has two types

o Masonry

o concrete pier

Drilled caissons

Well foundation or caissons are box like structurescircular or rectangular which are

sunk from the surface of either land or water to the desired depth

Caisson foundations are used for major foundation work such as

Bridge pier and abutments in river

Wharves and quay walls docks

Large water front structures such as pump houses, subjected to heavy vertical and

horizontal loads

Well foundations are caissons are hollow from inside, which may filled withstand and are

plugged at the bottom, the load is transferred to the perimeter wall called as steining

Stone Masonry

Definition:

The art of building a structure in stone with any suitable masonry is called stone masonry.

Types of Stone Masonry:

Stone masonry may be broadly classified into the following two types:

1. Rubble Masonry

2. Ashlar Masonry

1. Rubble Masonry:

The stone masonry in which either undressed or roughly dressed stone are laid in a suitable

mortar is called rubble masonry. In this masonry the joints are not of uniform thickness.

Rubble masonry is further sub-divided into the following three types:


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1. Random rubble masonry: The rubble masonry in which either undressed or hammer dressed

stones are used is called random rubble masonry. Further random rubble masonry is also divided

into the following three types:

a. Un coursed random rubble masonry: The random rubble masonry in which stones are laid

without forming courses is known as un coursed random rubble masonry. This is the roughest

and cheapest type of masonry and is of varying appearance. The stones used in this masonry are

of different sizes and shapes. before lying, all projecting corners of stones are slightly knocked

off. Vertical joints are not plumbed, joints are filled and flushed. Large stones are used at corners

and at jambs to increase their strength. Once "through stone" is used for every square meter of

the face area for joining faces and backing.

Suitability: Used for construction of walls of low height in case of ordinary buildings.

b. Coursed random rubble masonry: The random rubble masonry in which stones are laid in

layers of equal height is called random rubble masonry. In this masonry, the stones are laid in

somewhat level courses. Headers of one coursed height are placed at certain intervals. The stones

are hammer dressed. Suitability: Used for construction of residential buildings, go downs,

boundary walls etc.

2. Squared rubble masonry:The rubble masonry in which the face stones are squared on all

joints and beds by hammer dressing or chisel dressing before their actual laying, is called

squared rubble masonry.

There are two types of squared rubble masonry.

a. Coursed Square rubble masonry: The square rubble masonry in which chisel dressed stones

laid in courses is called coarse square rubble masonry. This is a superior variety of rubble

masonry. It consists of stones, which are squared on all joints and laid in courses. The stones are

to be laid in courses of equal layers. and the joints should also be uniform. Suitability: Used for

construction of public buildings, hospitals, schools, markets, modern residential buildings etc

and in hilly areas where good quality of stone is easily available.


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b. Un coursed square rubble masonry: The squared rubble in masonry which hammer dressed

stones are laid without making courses is called un coursed square rubble masonry. It consists of

stones which are squared on all joints and beds by hammer dressing. All the stones to be laid are

of different sizes. Suitability: Used for construction of ordinary buildings in hilly areas where a

good variety of stones are cheaply available.

3. Dry rubble masonry: The rubble masonry in which stones are laid without using any mortar

is called dry rubble masonry or sometimes shortly as "dry stones". It is an ordinary masonry and

is recommended for constructing walls of height not more than 6m. In case the height is more,

three adjacent courses are laid in squared rubble masonry mortar at 3m intervals.

2. Ashlar masonry:

The stone masonry in which finely dressed stones are laid in cement or lime mortar is known as

ashlars masonry. In this masonry are the courses are of uniform height, all the joints are regular,

thin and have uniform thickness. This type of masonry is much costly as it requires dressing of

stones.

Suitability: This masonry is used for heavy structures, architectural buildings, high piers and

abutments of bridges.

Ashlars masonry is further sub divided into the following types:

hlar masonry

Ashlar fine or coursed ashlar masonry: In this type of stone masonry stone blocks of same

height in each course are used. Every stone is fine tooled on all sides. Thickness of mortar is

uniform through out. It is an expensive type of stone masonry as it requires heavy labor and

wastage of material while dressing. Satisfactory bond can be obtained in this type of stone

masonry.


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Random coursed ashlar masonry: This type of ashlar masonry consists of fine or coursed

ashlar but the courses are of varying thick nesses, depending upon the character of the building

Rough tooled ashlar masonry: This type of ashlar masonry the sides of the stones are rough

tooled and dressed with chisels. Thickness of joints is uniform, which does not exceed 6mm.

Rock or quarry faced ashlar masonry: This type of ashlar masonry is similar to rough

tooled type except that there is chisel-drafted margin left rough on the face which is known as

quarry faced.

Chamfered ashlar masonry: It is similar to quarry faced except that the edges are beveled or

chamfered to 450 for depth of 2.5 cm or more.

-in course masonry: It is the name given to a class of ashlar masonry which occupies an

intermediate place between rubble and ashlars. The stones are all squared and properly dressed.

It resembles to coursed rubble masonry or rough tooled ashlar masonry.

Ashlar facing: Ashlar facing is the best type of ashlars masonry. Since this is type of masonry

is very expensive, it is not commonly used throughout the whole thickness of the wall, except in

works of great importance and strength. For economy the facing are built in ashlars and the rest

in rubble.

Brick masonry

cher bricks on edges instead of bed

This bond is weak in strength but it is economical Brick masonry is made up of brick units

bonded together with mortar

Components of brick masonry


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Types of mortar

-lime mortar

Types of bricks

Traditional bricks

It has not been standardize in size

Dimensions varies from place to place

Thickness varies from varies from cm to 7.5cm,widthvaries from 10to13 cm and length varies

from 20to25 cm

Modular brick

Any brick which is the same uniform size as laid down by bis

The nominal size of the modular brick is 20cm x10cmx10cm

Actual size is 19x9x9

Classes of brick

Bonds in brick work


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Single Flemish bond

Single Flemish bond is comprised of double Flemish bond facing an English bond backing and

hearting in each course

Facing bond

This bond is used where the bricks of different thickness are to be used in the facing and backing

of the wall

The nominal thickness of facing brick is 10 cm and that of backing bricks is 9 cm the header

course tis provided at a vertical interval of 90 cm

English cross bond

This is he modification of English bond to improve the appearance e of the wall

Brick on edge bond

This type of bond uses stret

dutch bond

DAMP PRPOOF COURSE

Introduction

One of the basic requirements of the building is that it should remain dry or free from moisture

traveling through walls, roofs and doors

Dampness is the presence of hydroscopic or gravitational moisture in the building

Dampness gives rise of un hygienic condition, and reduction of strength of structural components

Every building should be damp proof

Causes of dampness

Moisture rising up from the ground to the walls

Moisture constantly travels through the substructure. in impervious soil lot of soil moisture

present in the soil this moisture may rise up in the wall and floor trough capillary action

Ground water rise will also result in moisture entry into the building through walls and floors

Rain travel from wall tops

If the walls are not properly protected from rain penetration, rain will enter into the wall and

travel down

Leaking roofs will also permit the water to enter in the wall


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Rain beating against external walls

Heavy showers of rain may beat against external walls

If the balconies do not have proper outward slope water will enter in the building interior and it

would completely deface the decoration of the wall

Condensation

Due to condensation of atmospheric moisture water is deposited on the

Walls, floors and ceilings

Methods of damp proofing

Membrane damp proofing

Introducing a water repellent membrane or damp proof course between the source of dampness

and the part of the building adjacent to it .

Dpc may be consist of flexible materials such as bitumen, mastic asphalt, bituminous felts,

plastic are polythene metal sheets .

Integral damp proofing

This consist of adding certain water proofing compounds of materials to the

concrete mix so that it becomes impermeable

These water proofing compounds made from

Chalk, talk and fullers earth

Compounds like alkaline silicates, aluminum sulphate, and calcium chloride


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Surface teatement

This consist of application of layer of water repellentsubstance or compounds on the

surface through which moisture enters

The use of metallic soap such as calcium and aluminium oletes and stearates are much

effective against rain water penetration

Surface treatment is effective only the moisture is superficial and its not under pressure

Cavity wall construction

this is an effective method of damp prevention in which the external wall of the building

is shielded by an outer skin wall leaving a cavity between the two guniting

This consist of depositing under pressure ,an impervious layer of rich cement mortar over

the exposed for water proofing or over pipes for resisting the water pressure

Cement mortar consist of 1:3 cement sand mix which is short on the cleaned surface with

the help of cement gun under a pressure of 3to 4 kg/cm2

Pressure grouting

This is the process of forcing cement grout under pressure, into cracks, voids, fissures etc

present into the structural components

This method is quite effective in checking the seepage of raised ground water

Materials used for damp proofing course

Hot bitumen

Mastic asphalt

Bituminous or asphaltic felts

Metal sheets

Combination of sheets and bituminous felts

Bricks

Stones

Mortar

Cement concrete

Plastic sheets


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FLOORS

The purpose of floor is to provide a level surface capable of supporting the occupants of the

building, furniture, equipment and some time interior wall

The floor must satisfy the following requirements

resistance

Components of a floor

Sub floor, basecourse or floor base

Floor covering or flooring

Selection of flooring materials

Factor that affect the choice of flooring


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Types of flooring

ng cement concrete flooring

Mud flooring and muram flooring

This type of flooring is cheap, hard highly impervious

It is easy to construct and easy to maintain

It has good thermal insulation property due to which it remains cool in summer and warm in

winter

Over a well prepared ground 25 cm thick selected moist earth is spread and it rammed well to

compacted thickness of 15cm

In order to prevent cracks small quantity of chopped straw is mixed

Muram flooring

Muram is a form of disintegrated rock with binding material

To construct such a floor a 15 cm thick layer muram is laid over prepared sub grade over it 2.5

cm thick powder layer of muram is spread and rammed

Brick flooring

The sub grade is compacted properly, to the desired leveland 7.5 cm thick layer is spread

Over this a course of brick is laid flat in mortar is built

Such flooring is used in cheap construction, especially where good bricks are available


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Tiled flooring

Tiledflooring is constructed from square ,hexagonal or other shapes made up of clay

cement concrete and terrazzo

These are available In various thickness

Thes are commonly used in residential houses ,schools,hospitals and other public

buildings

Over the concrete base a 25 to 30 mm thick layr of lime mortar 1:3 to serve as a bedding

The bedding mortar is allowed to harden for 12 to 24 hours

Neat cement slurry is spread over it and the tiles are laid flat over it

Marble flooring

It is the superior type of flooring used in bathrooms and kitchens of residential building

and hospitals ,sanitorium ,temples etc

After the preparation of base concrete 20 mm thick bed layer of 1:4 cement mix spread

under the area of each individual slabs.

The marble layer is then laid over it and pressed with wooden mallet and leveled

Timber flooring

Timber flooring is used for carpentry halls ,dancing halls auditorium

Etc

These are not commonly usedin India because its costlier

But hilly area where wood is available and temperature drops very low timber flooring is

quite common

The suspended type of wooden floor is supported above the ground

The solid type of wooden floor is fully supported on the ground

SCAFFOLDING

When te higt of wall or column or othet structural member of a building exceeding1.5 m

temporary structures needed to support trhe platforms over which the work man sit and carry o

the work

These temporary structures constructed very close to the wall is in the form of imber o steel

frame work commonly called as scaffoldings


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Components of scaffoldings

or needle scaffoldings

Single scaffoldings

This consists of a single frame work of standards, legers, put logs etc

Constructed parallel to the wall at a distance of about 1.2 meters

The standards are placed at a distance of 2to2.5m interval

Ledger connected with the standards, and are provided at a vertical distance of 1.2to 1.5 m Put

logs or connected with one end on the ledgers and other end at the holes of the wall at an interval

of1.2 to 1.5 m interval


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Double are masons scaffoldings

It is very difficult to put holes in walls to m support putlogs in stone masonry

In the case a strong scaffolding is used consisting of two rows of scaffolding

The first row placed 20 to 30 cm away from the wall the other frame will 1m distance

from the first one

Put logs are the supported on both the supports, rakers and cross braces are provided to

make the scaffolding more strong

It also called as independent scaffoldings


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Cantilever or needle scaffolding

Cantilever supports can be used under following circumctances

Ground is week to support standards

Construction of the upper part of the wall is to be carried out

It is required to keep the ground near wall free for traffic etc i

It ha s two types

Single Frame

Te standards are supported on series of needle taken out through opening or through holes

Double frame

The needles are projecting beams are strutted inside the floors

Suspended scaffolding

It is the light weight scaffolding used for repair works such as pointing, painting etc

The working platforms are suspended from roofs by means of wire ropes or chains etc

Trestle scaffolding

Such type of scaffoldings are used for painting and repairing work inside the room up to a height

of 5m

The working platform is supported over the top of movable contrivances such as tripods ladders

etc

Steel scaffolding

Steel scaffolding is practically similar to the timber scaffolding, here wooden members

are replaced by steel couplets are fittings

Such scaffolding can be erected and dismantled rapidly

It has a greater strength and greater durability

Patented scaffolding

Many patented scaffolding made of steel are available in the market

Thos scaffoldings are equipped with special couplings frames etc

TRUSSES

Trusses are the frame formed by number of straight members connected in the form of

triangles

The embers are made by steel angles and they are joined by rivet or welding, these joints

are called nodes


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It is assumed that the external loads act at the nodes only and the members are subjected

to only tension or compression

The compression members are called as struts and the tension members are called as ties

Steel roof trusses are used under the following condition

Large spans are to be covered

Intermediate columns are to be avoided to have an unobstructed working area inside

There is a heavy rain or snow fall

Types of roof trusses

King post truss Here t he common rafters are supported by wooden frame work called truss under

required interval

The frame work consist of a king post, two struts two principal rafters and tie beam

The truss rest on stone bed blocks at either end

The common rafters rest on wooden purlins which in turn are fixed to the principal rafters

of the truss

The king post connect the ridge post and the middle of the tie beam

The struts are connected to the king post at the bottom and the principal rafters at the top

The roofing material is fixed to the common rafters king post truss is used for spans of

5m to 9m


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Queen post truss

The frame work consist of two principal rafters ,two queen post one straining sill two

struts one tie beam and one straining beam

The common matters rest on wooden purlins

The staining beam resist the horizontal thrust developed

The struts are connected to the queen post at the bottom and the principal rafters at the

top

North light roof truss

North light or saw tooth roof truss is special type of roof trusses suitable for factories

engaging in manufacturing work North light truss is sawtooth

Actual lighting is taken an advantage during day time by using the north light roof trusses

In this type of trusses vertical drops are provided this drops are covered with glasses so as

to permit light in to the interior

Centering and shuttering


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Shuttering is the temporary ancillary construction used as a mould for the structures

In which the concrete is placed and allowed to hardened

These are classified as steel wooden plywood combined woods steel, reinforced concrete

and plain concrete

Requirements of shuttering

The material should be cheap and should be suitable for re use several times

It should be practically water proof so that it should not observe water from concrete

It should be strong enough to with stand all loads coming on it

It should be stiff enough so that deflection is minimum

The surface of the formwork should smooth and it should afford easy stripping

Loads on form work

Live load due to labour etc

Dead weight of wet concrete

Hydrostatic pressure of the fluid concrete

Impact due t pouring concrete

Shuttering for column

Components

Sheeting or column shutter all around the column

Yokes

Wedges

bolt


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Shuttering for beam and slab floor

The slab is continous over the beam

The slab is supported on 2.5 cm thick sheeting laid parallel to the main beam

form work for stairs

Shuttering of walls

The boarding may be 4 to 5 cm thick for walls up to 3to 4m high

The boards are fixed to 5cmX10cm posts known as struts are soldiers

ROOF FINISHING Roof finishing accessories include all types of accessory materials that are used to finish

a roof. Flashing, drip edge, and roof drains are all examples of roofing accessories.

Roof finishing accessories are widely available for a range of applications and may be

chosen for functional, aesthetic, or budgetary reasons.


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Roofing accessories are largely made from aluminum, steel, copper, or PVC vinyl. They

include a range of products including

Rain gutters and Drains and guards

Flashing or weatherproofing materials

Rain gutters and Drains and guards

Rain gutters, drains and guards are roof finishing accessories that collect and divert rainwater

away from the roof and building foundation.

These types of roof finishing accessories may also reduce erosion, prevent leaks in the

foundation or basement, reduce water exposure on painted surfaces, and collect water for

additional use.

Rain gutter, drain and guard roof finishing accessories may be available with screens, louvers, orhoods for additional protection.

Flashing or weatherproofing materials

Roof finishing accessories also include flashing, also known as weatherproofing.

Flashing refers to installing a thin, continuous piece of sheet material to prevent the passage of

water into the structure from a joint or angle.

Flashing roof finishing accessories are commonly used around protruding objects in the roof,

such as chimneys or pipes, to prevent water from reaching seams or joints.

Roof caps, drip edges, ridges and shingles, and chimney caps

Roof caps, drip edges, ridges and shingles, and chimney caps are also common, functional roof

finishing accessories

. Roof caps provide ventilation via the rooftop. They are commonly made from copper or

galvanized steel, and often include an insect screen.


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Drip edge roof finishing accessories are useful in stopping water from seeping under a roof deck,

which can prevent frame rot.

Roof ridge caps and shingles are also used as finishing accessories. Roof shingles are individual,

overlapping elements used for water-resistance.

At the roof ridge, there is typically a copper, lead, or plastic cap to ensure water protection.

Ridge vents are also commonly used as roof finishing accessories to provide ventilation to attic

or upper crawlspaces.

Leader boxes, Finials and turrets and Weathervanes.

Finishing accessories can also be decorative.

These accessories include leader boxes, finials and turrets, and weathervanes. Leader box

accessories are used with gutter systems to hide or diminish the sight of leader elbows, and are

available in a range of decorative styles, shapes, and designs.

Roof finials and turrets are caps or towers affixed to the highest point of the roof, largely for

decoration. Turrets are often designed to hold clocks or bells.

Similarly, weathervanes are another type of roof finishing accessory often used for decoration at

the highest point of the roof. Weathervanes are not solely used for decoration, however, as they

also point to the direction of the wind. Other, unlisted types of roof finishing accessories may

also be available.

ACOUSTICSAcoustics is the science of sound ,which deals with origin ,propagation and auditory sensation of

sound and also with design and construction of different building units to set optimum condition

for producing and listenig speech musi etc

FIRE PROTECION

No building material is perfectly fire proof

A wider interpretation of the fire safety may be deemed to cover the following aspects

Fire prevention and reduction of number of out breaks of fire

Spread of fire both internally and externally

Safe existence of any and all occupants in the event of an out breaks of fire

Fire load

Fire load is the amount of heat in kilocalories which is liberated per square meter of floor area of

any combustible parts of the building itself


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The fire load is determined by multiplying the weight of all combustible materials by their

calorific value and dividing the floor area under consideration

Grading of building according to fire resistance

The national building code of India (sp:7-1970) divides building in to the following four types

according to the fire load the building is designed to resist

Type 1 construction all structural components have 4 hours fire resistance

Type 2 construction all structural components have 3 fire resistance

Type 3construction all structural components have 2 hours fire resistance

Type 4 construction all structural components have 1 hour fire resistance

General fire safety requirements for buildings

All building and particularly building having more than one storey shall be provided with

liberally designed and safe fire proof existence

The exist shall be so placed that they are always immediately accessible and each is

capable of taking all the persons on that floor a s alternative escape route

Escape route shall be well ventilated as persons using the escapes are likely to over come

from smoke Fire proof door shall conform rigidly to the fire safety requirements

Electrical and mechanical lifts while reliable undr normal condition may not always be

relied on escape purpose

Lift shafts and stairways invariably serve as flues are tunnels thus increasing the fire by

increased draught

Floors are required to withstand the effect of fire for full period stated for the particular

grading

Roofs of the various fire grades of the building shall be designed and constructed to

withstand the effect of fire for the maximum period


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UNIT III SUB STRUCTURE CONSTRUCTION 13

TECHNIQUES OF BOX JACKING

Necessity of this technique

When the increasing demands for various forms of transport infra structure to be constructed in

congested locations or below existing facilities the need to be able to install large structures

without destruction is a growing need.

The jacking of large boxes to create an underpass below a railway track or road without

destruction

For around 30 years this box jacking techniques has found wide use Europe and India

Types of structures under jacking

Box jacking

Arch jacking

Pipe jacking

OPERATIONS

The box shaped tunnel structures are pre fabricated units which are pushed into soil by

hydraulic jack

Soil is excavated at the advancing face by manual means or by excavators

To avoid settlements of over laying roads or rail track soil is excavated after it enters the

cutting heads Excavation ahead of the cutting is avoided the cutting head is moved forward in small

increments to avoid any having of the road or rail track

In addition to that, without stabilizing the soil, the box technique would cause the super

structure to settle the threatening structure failure so the ground ahead of tunnel boxes

needed to be frozen

PIPE JACKING

In tunnels of damages above 2m men and machines worked the tunnel phase exacting and

providing soil support to the excavator soil by erecting the lining. The tunnel diameter becomes

small it becomes difficult for workers to carry out soil excavation of in erect the tunnel lining

system with in the tunnel shield

For diameter in the range of 0.5m to 1.5m it is more efficient to excavate the soil by drilling

systems controlled from a shaft or a pit to push the tunnel lining segment from the shaft or pit


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these techniques are often referred to us pipe jacking or micro tunneling techniques and

equipments

Pipe jacking refers to a technique in which a man in a sitting or crouch position, users epic and

shovels to excavate tunnel face and the pipe is jacked forward from a shaft using hydraulic

jacking system

Horizontal auguring refers to a similar technique in which the man is replaced by a horizontal

continuous flight helical auger

INSTALLATION

The pipe sections are moved forward by hydraulic jacking and the miniature TBM derive its

reaction from these section

Pipe segments of length 1 to 3 diameters 0.5 to 2m can be jacked into the soil using reaction

from the concrete wall erected at the rior of jacking pit.

DIAPHRAGM WALL

In structural engineering, a diaphragm is a structural system used to transfer lateral loads

to shear walls or frames primarily through in-plane shear stress

. These lateral loads are usually wind and earthquake loads, but other lateral loads such as

lateral earth pressure or hydrostatic pressure can also be resisted by diaphragm action.

The diaphragm of a structure often does double duty as the floor system or roof system in

a building or the deck of abridge, which simultaneously supports gravity loads. Diaphragms are usually constructed of plywood or oriented stand board in timber

construction;

Metal deck or composite metal deck in steel construction; or concrete slab in concrete

construction.

The two primary types of diaphragm are flexible and rigid. Flexible diaphragms resist

lateral forces depending on the tributary area, irrespective of the flexibility of the

members that they are transferring force to

. On the other hand, rigid diaphragms transfer load to frames or shear walls depending on

their flexibility and their location in the structure.

Parts of a diaphragm include:

-plane shear


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s

since the membrane is usually incapable of handling these loads alone.

TUNNELING

Process of making tunnels in order to reduce distance of travel or traffic congestion for highway

and railway is called tunneling

Tunneling is important for the following purpose

o Time saving and reduction in fuel

o Avoid unwanted traffic congestion

o Maintain a proper speed

o Avoid tiredness of travel

o Avoid unwanted accidents

o To avoid deforestation and death of animal while crossing

o To avoid land slide in hilly region

o To avoid the long route around the mountain

o To reduce the length of highway and railway and it may be economical

o To have flatter gradient that is essential to maintain the speed of the vehicle

Tunneling types depending upon the shapes

Poly centric

Horse shoe

Size of the tunnel

It depends upon the number of track and the width and length of the mountain

Alignment of tunneling

o Identify the shortest route

o Height of mountain should be less

o Mark the points on the mountain

o Transfer the tunnel inside the mountain by making of required depth

o Checking the tunnel cross section whether equal every where


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Methods of tunneling

Shaft tunneling

Pilot tunneling

Shaft tunnels

Vertical passages are created along the line o the tunnel then the tunnels can be excavated by the

passage of having distance half of the distance between adjacent passage openings are available

to take the excavated material ,shafts can also be used to pump out the water

Pilot tunneling

If the height of the mountain is more then we can exercise this method of tunneling but uf he

horizontal length is more, shaft tunneling is done

PILE DRIVING

This is the process of inserting the pile inside the soil

It is a process by way of which a pile is forced in to the ground with out excavating the soil

Pile driving can be done by two methods

Using hammering

Using pile driver

Hammering

Heavy bl0w is given by means of a hammer

Variety of hammers available to perform some of the acion

hammer

Drop hammer

The hammer is lifted by a winch and dropped down

The hammer is connected to the rope by a hook

When it is lifted up after reaching a particular height it is dropped down


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Single acting hammer

Hammer is lifted by stream and dropped then it will fell down in the top of the pile by

gravitational force

Double acting hammer

It is the same as that of single acting but here both the lifting and dropping is done by steam

engine

Diesel hammer

The process of lifting and dropping is done by diesel engine

Vibrators

If the soil condition is loose ,then using some vibrators the pile is inserted

SHEET PILES

It is the type of pile that is made of concrete, steel or wood

The thickness of the pile is very less when compared to the length and width of the pile

To prevent the entry water in construction the sheet piles are used, this is also used to

separate the vertical member of the building

The piles are inserted by some machine the depth of the piles can be increased by proper

joints in successive installment

Functions

To enclose the site or part to prevent escape of loose soil

To retain the sides of trenches or excavation

To construct retaining wall in the marine structures

To prevent seepage below the dams or hydraulic structures to construct coastal defense

work

To protect the foundation from scouring action of nearby river

Concrete sheet piles

Reinforced precast unit having the width of 50 to 60 cm and thickness 2to 6cm and the depth can

be increased by further installment

Timber sheet piles

it is used only for temporary works ,the width of the pile varies from 225to 280 cm the thickness

shall not be less than 50mm


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DEWATERING

DEFINITION

When water table exists at a shallow depth below ground surface, it is essential to lower the

water so as to carry out construction of foundation, basement, and metro tunnels etc.This is

achieved by pumping out water from multiple wells installed at the site. The process is called as

dewatering.

Types of dewatering method

Dewatering can be done by adopting one of the following four strategies

Dewatering of soil by temporary lowering of water table using wells and pumps prior

excavation as depleted in figure

Allowing water to reap into excavation area, collecting it in sumps and pumping it out.

Before that adequate steps have to be taken to support the soil on sides of the excavated

area, to prevent washing away of fines and have sufficient space for the work area.

Making the soil around excavated zone impermeable by technique such as grouting are

freezing so that inflow of water is stop are minimized.

INSTALATION TECHNIQUE

Sufficient size and capacity of dewatering system is necessary to lower and maintain

ground water table and to allow material to be excavated in a reasonable dry condition.

Excavation slopes to be stabilized where sheeting is not required

Dewatering system is to be operated continuously until backfill work has been

completed.

Then, the structure to be constructed at the excavated area has to be finished

The complete stand by have to be available for immediate operation as may be required,

to adequately maintain dewatering on continuous basis and in the event that all or any

other part of the system may become inadequate or fail

The water removed from the excavation to be disposed in such a manner as will notendanger portions of work under construction or completed.

For dewatering purpose, well points deep well, caissons and tunnels are used.


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WELL POINTS

DEWATERING

When construction operation have to be excited below the ground water table level. Dewatering

of soil can be done by the following methods

Collecting water in sumps and pumping it out.

Installing well points small or deep wells and pumping out ground water

Using special technique in fine grained soils such as vaccum dewatering and electro-osmosis

WELL POINTS

To pump out the ground water small sized wells called well points are used for a more dry

working area the two methods used most often for lowering water table below the excavation

level are the well point method and the deep well method.

WELL POINT METHOD :

This is economical and useful for lowering the water table by 15m or less.

Incase of well point method or deep well method it is based on the fact that removal of

water by continuous pumping from a well causes the water table level to become

depressed and result in the formation of draw down.

When a series of wells are placed close to each other, the overall effect is lowering of the

water table level. Well points, being smaller, are easy to install.

Well points, can lower the water table by only 6.7m because the pump, is located at the

ground surface and connected to group of well points through a pipe, cannot lift water

from greater depth.

Beyond 7m, multistage well points are used.

DEEP WELL METHOD

This method is useful for lowering the water table by more than 15m.

Deep wells have larger diameter more depth and greater spacing.

The pump is located at the bottom of well and hence can pump out water from greater depth.

Deep wells become more economical if more points are required.


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UNIT IV SUPER STRUCTURE CONSTRUCTION

BRIDGE DECKS

The principal function of a bridge deck is to provide support to local vertical loads (from

highway traffic, railway or pedestrians) and transmit these loads to the primary superstructure of

the bridge, Figure 1(1). As a result of its function, the deck will be continuous along the bridge

span and (apart from some railway bridges) continuous across the span. As a result of this

continuity, it will act as a plate (isotropic or orthotropic depending on construction) to support

local patch loads.


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Continuity ensures that whether or not it has been designed to do so, it will participate in the

overall structural action of the superstructure. The overall structural actions may include:

of the longitudinal girders, Figure 1(2).

and cross girder structures, throughout the span, Figure 1(3).

longitudinal and cross girders, Figure 1(4).

It may be necessary to take account of these combined actions when verifying the design of the

deck. This is most likely to be the case when there are significant stresses from the overall

structural actions in the same direction as the maximum bending moments from local deck

actions, e.g. in structures with cross girders where the direction of maximum moment is along

the bridge.

The passage of each wheel load causes a complete cycle of local bending stresses. The number

of significant stress cycles is, therefore, very much higher for the deck than for the remainder of

the superstructure. In addition, some of the actions of the deck arising from its participation in

the overall behaviour are subject to full reversal;

an example is the transverse distribution of vertical load between girders. For both these reasons,

fatigue is more likely to govern the design of the bridge deck than the remainder of the

superstructure.

SHELL STRUCTURES

Shells are 3d structures constructed on storage tanks or roof for large column area such as indoor

stadiums, exhibition halls, theatres, complex churches etc


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Before analysis and design of foundation it is necessary to determine the soil characters

of the sea shore. Capacities of the available crains will influence the operational activities

of platform constructions.

The fixed platforms can be classified into

Jacket or template structures

Gravity structures

ERECTING LIGHT WEIGHT COMPONENTS ON TALL STRUCTURES

Besides high raise buildings the usage of steel element is also popular with construction

of hospital and commercial complexes

Instead of concrete beams and columns more than 6100 tonnes of steel have been used to

build the main frames

Light weight blocks are used for patricians to reduce the dead load building

The usage of permanent concrete form works and structural steel elements will be the

main constituter for erecting light weight components on tall structures results rapid

speed of constructions.

Hence the erection of steel beams and columns as well as the installation of concrete

form work consumes only less time

Self drilling tapping screws are the most prevalent fasteners. Steel to steel connections

can be carried out to connect struts or joist and track together

Entire can be erected manually with out the use of heavy equipment

All these structures require few battery powered screw gunes and some ropes and pulleys

No scaffoldings is require for assembly and disc assembly of the structures because the

structure itself provides the scaffoldings as it goes up or comes down

Almost any number of column sections can be added to make it any height we desire

During the construction of tall structures the following equipments areused for the aerial

transporting and handling

Aerial cable way

Helicopter


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UNIT V CONSTRUCTION EQUIPMENT

Construction equipments

Types of earth moving equipment

Classified into following types

e equipment

TRACTORS

Tractors are machine which change the engine energy into tractive energy

These are primarily used for pull or push the loads

They are also used for different purposes by mounting many types of accessories

Types of tractor

Crawler type or track type

Rubber tired or wheel typeThe tractor is multi purpose machine

Light models are used for agricultural or short haulage works

Heavy models are employed in earth moving works, cranes, shovels or special rigs

Wheeled types or employed in light but speedy jobs

Main constituents of tractor are engine ,clutch ,transmissonsystem,ground drive and

controls

Factors should be considered while selecting a tractor dozer

Size of the dozer for given job the type expected from the track to dozer

The type and condition of haul road

distance to be move


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Bulldozers

Dozers are machine designed primarily for cutting and pushing the material over short

distance

They consist with a front mounted blade controlled by hydraulic cylinder to vary the

depth of cut and rate of leveling depending on the material and application

a dozer is frame mounted unit with a blade, curved in its section, extending in front of the

tractor

Bulldozer is most versatile and most important equipment on construction project

Basically its pushing unit but its widely used as multipurpose equipment and can perform

large number of operations with minor changes

Scrapers

Scrapers are the devices to scrap the ground and load it simultaneously, transport it for the

required distance and dump it and then spread it for the required area

The scrapers are designed to dig,load,haul,dump and spread

The scrapers are of three types

Towed type

The towed type scrapers are provided with either cable or hydraulic control

It can be operated in extremely adverse condition

Conventional scrapers

These are generally manufactured from 10to 25cubicmetres

Self loading scrapers

These are twin engine scrapers

It can work completely independently of all other plants

It has the following parts

Bowl


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Cutting edge

Apron

Tail gate or ejector

Following or three major operations of scrapers

Loading or digging

Transporting

Unloading

SELECTION OF EQUIPMENT

Proper selection of construction equipment place a vital role in the speedy and

economical completion of the construction

Following are the main points which should be considered while selection off the

construction equipments

Suitable for job condition

The equipment must meet the requirement of the work climate and working condition

Size of the equipment

Size of the equipment it should be such that must be able to be used with other

equipments

If the equipment selected for larger size it will remain idle inmost of the time

Standardization

It is better to have same type and size of equipment in a construction then it is easy to

have spare parts, and to understand its operations

Availability of equipment

Availability of spare parts

Multi purpose equipments the selected equipments must be capable of performing

various operations

Availability of know how

The equipments selected should be satisfactorily handled by the available operators and

machine

Use in future projects

The economical aspects


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Static compaction equipment

It has several types

Towed static smooth compactors

Smooth rolls where the first type of rolling compaction equipment used

These where pulled by men or horses and were first used by Romans to smoothen there roads

Static sheep foot or pad foot compactors

When compacting the earth the feet penetrate deep in to th e loose material during the first passes

and compact the soil from bottom up

The kneading effect of sheep foot compactors is used to break up the

Earth lumps and reduce the air voids

Static three wheeled self propelled compactors

These have three rolls a small usually split steering role in the front

Two large drive rolls mounted on rear axle at both the end

Static tandem compactors

Tandem rolls have two equal sized rolls and are centered in line tandem

These are used for the compaction of bituminous layer as they leave a smooth surface

Vibratory compaction equipments

It can be divided in to following types


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Equipment for concrete mixing

Concrete mixers

For small jobs conc. mixers are used to mix the ingredients of the concrete

Following type of concrete mixers are used in the construction

Hand felt tilting drum mixers

These are smaller capacity mixers ,aggregate cement and water fed in to the drum by hand

Loader fed tilting drum mixers

These are larger capacity as compared to hand fed mixers

These are fixed with the loading hopper operating by the wired rope for loading

Reversing drum mixers

This type of mixer is used on comparatively larger works

The mixer drum is horizontal and it is non tilting type

It has blades which work alternatively

Roller pan mixersThese mixers are primarily used for mortars ,the rollers and mixer blades rotate in a pan and not

only mixing material but also kneading and crushing it

Tunneling equipment

Selection of equipment

Selection of equipment for tunneling depends upon quantum of work involved

So that the tunneling work is carried out economically,speedly and safely

Muck loading

Mucking is the operation of loading the broken rock or earth for removal from tunnel

Mucking process can be done by the following e

Construction Techniques,Equipments and Practices

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